The present invention relates in general to integrated circuits, and more particularly to electromagnetic devices fabricated on a dielectric substrate or semiconductor wafer.
Wireless communications devices are benefiting from advancements in semiconductor technology which have led to increased levels of integration and higher operating frequencies. For example, cellular telephones and pagers used these advancements to increase their functionality and reliability while reducing their physical size, power consumption and manufacturing cost. However, an obstacle to further integration is the inability to fabricate a cost effective inductor having a high inductance and quality factor ("Q") at frequencies greater than one gigahertz. Moreover, the growing use of filters in communications devices has increased the need for such an inductor which can be integrated on a dielectric or semiconductor substrate die with other circuitry.
Prior art integrated inductors typically consume a large substrate area in order to achieve adequate inductance values, which adds substantial cost to an integrated circuit. When high permeability materials are used to increase the inductance per unit area, the inductors suffer from an inadequate Q due to parasitic substrate eddy currents induced by the magnetic flux leakage at the periphery of the high permeability material.
Hence, there is a need for a high inductance, high Q inductor that can be integrated on a semiconductor die long with other circuitry.